class PromiseKB{
  
}
//在手写的promiseXXX.js添加以下代码，其中改成自己定义promise.js名字
PromiseKB.defer = PromiseKB.deferred = function(){
let dfd = {};
dfd.promise = new Promise((resolve, reject)=>{
  dfd.resolve = resolve;
  dfd.reject = reject;
});
return dfd;
}
module.exports =  PromiseKB